SIS DRI module unresolved symbols

I'm trying to set up a friend of mine with a Linux box (RedHat 7.2 - XFree86 4.1.0). I'm running into problems getting the SIS DRI module to load into the kernel because sis_malloc and, I believe sis_free do not resolve. I tried compiling it into the kernel, but the link at the end failed, for the same reasons. The details:

<*> /dev/agpgart (AGP Support)

[*]   Intel 440LX/BX/GX and I815/I830M/I840/I850 support             
[*]   Intel I810/I815/I830M (on-board) support                       
[*]   VIA chipset support                                            
[*]   AMD Irongate, 761, and 762 support                             
[*]   Generic SiS support                                            
[*]   ALI chipset support                                            
[*]   Serverworks LE/HE support                                      
[*] Direct Rendering Manager (XFree86 DRI support)                   
[ ]   Build drivers for old (XFree 4.0) DRM                          
--- DRM 4.1 drivers                                                  
<M>   3dfx Banshee/Voodoo3+                                          
<M>   ATI Rage 128                                                   
<M>   ATI Radeon                                                     
<M>   Intel I810                                                     
<M>   Matrox g200/g400                                               
<*>   SiS                                                            

This produces:
... -o vmlinux
drivers/char/drm/drm.o: In function `sis_fb_alloc':
drivers/char/drm/drm.o(.text+0x6893): undefined reference to `sis_malloc'
drivers/char/drm/drm.o(.text+0x68d6): undefined reference to sis_free' drivers/char/drm/drm.o: In function sis_fb_free':
drivers/char/drm/drm.o(.text+0x69c8): undefined reference to sis_free' drivers/char/drm/drm.o: In function sis_final_context':
drivers/char/drm/drm.o(.text+0x6e4e): undefined reference to `sis_free'

Granted, he does have the one chipset not supported: 5591/5592. Nonetheless, the kernel should still compile and link. Anyway, here's his lspci output:

00:00.0 Host bridge: Silicon Integrated Systems [SiS] 630 Host (rev 21) 00:00.1 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE] (rev d0)
00:01.0 ISA bridge: Silicon Integrated Systems [SiS] 85C503/5513 00:01.1 Ethernet controller: Silicon Integrated Systems [SiS] SiS900 10/100 Ethernet (rev 83)
00:01.2 USB Controller: Silicon Integrated Systems [SiS] 7001 (rev 07) 00:01.3 USB Controller: Silicon Integrated Systems [SiS] 7001 (rev 07) 00:01.4 Multimedia audio controller: Silicon Integrated Systems [SiS] SiS PCI Audio Accelerator (rev 02)
00:02.0 PCI bridge: Silicon Integrated Systems [SiS] 5591/5592 AGP 01:00.0 VGA compatible controller: Silicon Integrated Systems [SiS] SiS630 GUI Accelerator+3D (rev 21)

The same thing happens with 2.4.17 .

Thanks for your help.